Mail forwarding:
If you move and want to have your mail forwarded to your new address, you can go to any post office with your ID (AR)card. Tell the counter staff that you want 주소이전신청서비스 (Joo so iee jeon service). S/he will then check your current (or old) address on your ID - ARC (card). Doing so online is not yet an option for foreign nationals. This service is free of charge for 3 months.